Blimey it's scary that a representative for a manufacturer should be talking such garbage ! Maybe he is just ignorant of the engineering of European cars. He should do some research and try spelling with the words tyre and crossply which are the non-American words for tire and biasply.
As Eric points out an Amphicar with front tyre pressure at 35psi is pretty much undriveable.
Amphicar wheels are same as Mercedes. Mercedes changed the rim design in about 1966 to add the rib to keep the tyre on. Tubeless tyres didn't appear before the mid 1970s and fitting a tube was still common at least 10 years after that.
As for "mythbusters" - I've seen that show on one of the satellite channels, a couple of blokes messing about in a shed - if he thinks that's a scientific experiment or that there is any validity in what they do beyond TV entertainment than he really is an idiot !
The accident reports are out there for vehicle roll overs caused by using tubeless tyres on rims designed for tubes. Amphicar is more at risk because of the high centre of gravity and the low front tyre pressure needed.
However Amphicar isn't (normally) driven aggressively and most owners cover very few road miles which certainly reduces the risk - and the risk will be acceptable for many, after all Amphicar has no ABS brakes, air bags, side impact protection, roll over bars and most Amphicars in the USA don't even have seatbelts. All these things are in the "risk" pot that the owner/driver needs to be aware of so they can then make their own decision about what to do - but that should be based on the facts, not the bowlucks (Saxon English word !) that this guy is talking.
David C
ps - quick search of Google spelling tyre the English english way and first result is this article from Australia
http://www.ebroadcast.com.au/ecars/Mitsubishi/Pajero/RollOver.html
"showing the result of tubeless tyres rolling off the rims in a sideways slide at about 70kph."
----- Original Message -----
From: Brian Crombie
To: david@manbus.com
Sent: Monday, September 15, 2008 9:29 PM
Subject: RE: [General Amphicar Discussion-t-20162] Re: Radial tyres again!
The following e-mail is a response from the "answer guy" at Diamond Back Classic Tires. I put the inner tube question to him last week and this is what he has to say. He states that they have asked Myth Busters to perform some tests. I officially nominate Dave Derer to provide an Amphicar with a custom roll cage to help settle this argument. Any seconds on this notion?
Brian,
I have heard both sides of this argument. It appears to me they Amphicar owners are split about 50/50 on this issue of running tubes. The last rationale I heard for running tubes on an Amphicar was that if the current caused the car to drift sideways and the tires hit bottom, the tire could unseat and you would be unable to drive out of the water onto land with a flat tire. I am sure that it would difficult if not impossible to change a tire while afloat.
In the quote you give from the forum the poster states " I just went through this and was told that I must use Tubes for safety reasons". He doesn't say who told him this. I have seen a statement in the catalog of a well known classic tire company as follows - "Older rims that were originally designed for bias-ply tires may crack if used with modern radial tires." Radial tires according to the United States Department of Transportation put less stress on a rim than does a bias ply tire. So, if that company is the one that came up with this, I would take it with a grain of salt.
All I can add to the conversation is that there is a lot myths and old wives tales floating around in the car collector community. Some of them appear to be spread by people that want to sell wheels or tubes, others by people that are sincere but have been "taken in" by people they had confidence in.
Several facts that may help you make up your mind as to which side you fall on:
1. When tubeless tires were introduced, they were designed to run on the thousands if not millions of cars that were currently on the road without requiring the purchase of new rims.
2. If you put a tube in a modern tubeless radial tire, you will need to remove the small paper stickers on the inside of the tire (these are stickers placed in the tire by the mfg for inventory control or quality control reasons) You will also need to put some talcum powder in the tire with the tubes. If this is not done, the tube could begin leaking air within 50 miles.
Unlike bias ply tires with their thick stiff sidewall, radial tires are designed to have sidewalls that flex to allow the tread to remain in complete contact with the road. This flexing is what causes an excessive amount of rubbing between the tubeless tire's inner lining and the tube. I guess you can say that tubeless tires are not designed for tubes.
We sell radial tubes for the people that need to run tubes, so I will be glad to sell you some if you would feel safer with tubes in your tires. The radial tubes are $12.50 each when bought with a set of our tires. If you decide to run tubes, be sure to remove the paper stickers on the inside of the tires and to use talcum powder.
If I owned a Amphicar I would put tubeless radial tires on it without tubes. I would run a minimum of 35 psi.
I have talked with several car owners that have experienced the leaking tubes when they put tubes in their radial tires because they are running wire wheels that will not hold air. Two claimed they had a flat tire within 50 miles. The leaks were caused by the paper stickers in the tires. I have never talked to a car owner that has had a tubeless tire "unseat from the rim" during an evasive action. Not saying that it hasn't happened, just that the people I have heard claiming this always say it happened to a friend of a friend of their third cousin twice removed - or somethihg similar. We have submitted a request to Myth Busters to test tubeless radail tires on older rims that came with tube type bias ply tires to separate the fact from the fiction.
Removing those little paper stickers is quite an ordeal. With most of them, you have to use a dremel tool with a small wire brush to remove the sticker. Since you can't even feel the sticker with you finger tips, it most be the difference in friction between the slick paper and the rubber inner liner that causes the break in the tube.
Richard
-----Original Message-----
From: Brian Crombie [mailto:Brian.Crombie@poly-tex.com]
Sent: Thursday, September 11, 2008 1:41 PM
To: info@dbtires.com
Subject: A need for inner tubes?
Richard,
The forum post below is a recent discussion regarding the need for inner tubes with any radial tire used on an Amphicar. The Amphicar rims apparently do not have a "bead lock" design which prevents a sudden air loss when the tire becomes highly stressed.
I am kindly asking that you clarify a need or no need for an inner tube using your product on this type of rim.
Many thanks for your input!
Brian Crombie
Faribault, Minnesota
'64, '65, '67 Amphicar owner
International Amphicar Owners Club member
www.amphicar.com
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Quote:
Originally Posted by canitfloat
I just went through this and was told that I must use Tubes for safety reasons. The design of the Amphicar rim is for tube type tires only and if you run tubeless tires on these rims the integrity of the seal could be lost when you least expect it causing instant deflation of the tire! Tubes cost about $10 ea. Because of their reputation, I got the Diamond back wide whites. Dont forget to blast, epoxy prime, 2k prime, wetsand and paint your rims 1st!
YES! I can not stress this enough! Amphicar rims do not have a bead lock type rim. If you go tubeless and have to make a hard turn (evasive action) you stand a real good chance of rolling the tire off the rim. You could end up flipping the car. Just because they will hold air, does not make them tubless rims.
TIP - Use an old tube to make a liner to cover the rim. Cut it so you have just the inside section left to line your rim, protecting the tube from rubbing on the rivits inside the rim. Keep a can of fix-a-flat with you too.
